For operation on the U.S. interstate highway system, commercial vehicle configurations must comply with federal size and weight regulations (See, Code of Federal Regulations, Title 23, Part 658, Truck Size and Weight). Currently there are two common, federally-compliant tractor truck-trailer combinations: a tractor with a single 48 to 53 foot semi-trailer; and a tractor with a tandem of two, coupled, 28 foot semi-trailers. In the tandem semi-trailer-trailer arrangement, the second trailer is typically connected via a kingpin to a fifth wheel carried on an added convertor dolly which, in turn, is connected to the first trailer via a drawbar/pintle hook.
Some LCV (Long Combination Vehicle) configurations are permitted in a few Western US states. Examples of LCV configurations include a tandem of two 48 foot or longer trailers, a tandem of a 48 foot or longer trailer and a coupled 28 foot trailer, and a set of three coupled 28 foot trailers. However, LCV arrangements are not permitted under federal regulations and therefore are restricted to specific routes or areas of operation.
There are commonly used fixed add-on van bodies (called dromedary boxes) which may be mounted on the truck tractor frame and used to haul limited extra freight.
Many loads are volume sensitive and “cube-out”, meaning the trailer volume is filled before the trailer weight limit is reached. This type of load is less efficient and generates unnecessary cost to the shipper (more trips are needed) and to the environment as more fuel is burned for the extra trips.
There is thus a need in the transportation industry to increase volume in truck tractor-trailer combinations within federal size and weight regulations. There is a need in the transportation industry to maximize freight loads (for both volume and weight). Resolving these needs will lower shipping costs, reduce fuel consumption by allowing fewer trips to move goods, and reduce highway congestion by having fewer trucks on the road.
The invention is directed to a novel truck tractor and trailer combination that fills this need. The invention comprises individual truck tractor and trailer components that in combination improve volume efficiency while complying with federal highway regulations and preserving the adaptability of the individual components.
The invention includes a van body or body unit mounted on a frame and having an axle assembly with a set of wheels on the frame extended behind the body. A coupling apparatus integrally mounts the van body to a truck tractor so as to form a non-horizontally articulated vehicle. A fifth wheel is provided at the rear end of the van body frame for connecting a conventional semi-trailer. Thus, a truck tractor and van body combination can selectively pull a semi-trailer.
Alternatively, the van body can be articulatedly coupled to the truck tractor at a fifth wheel on the truck tractor, thus forming a truck tractor-trailer combination.
According to the invention, a truck tractor and removable body unit system selectively configurable as a tractor and freight box combination or as an articulated truck tractor-trailer combination includes a truck tractor having a frame supported on a drive axle and a steer axle and having a fifth wheel mounted on the frame, and a body unit having a body mounted on a frame, the frame supported on an axle/wheel assembly and having a king pin for releasably engaging a fifth wheel, a coupling mechanism for releasably coupling the truck tractor frame and the body unit frame allowing relative vertical pivoting movement and constraining relative lateral movement between the truck tractor and body unit about the king pin and fifth wheel, the coupling mechanism releasably coupling a rear of the truck tractor frame to a location on the body unit spaced from the king pin, and an adjustable spring (e.g., an air spring) mounted to one of the truck tractor and body unit to act between the truck tractor frame and the body unit frame to adjust a loading between the truck tractor frame and body unit.
According to an aspect of the invention, the coupling mechanism includes a pair of laterally extending pins mounted to opposite sides of one of the truck tractor frame and body unit frame, and a pair of coupling plates mounted to opposite sides of the other of the truck tractor frame and body unit, the coupling plates each including a vertically oriented slot shaped to accept a pin and allow relative vertical movement of the pin in the slot.
According to another aspect of the invention, a trailing portion of the body unit frame extends beyond an end of the body, the axle assembly being mounted on the extended frame portion. A fifth wheel may be mounted on the trailing portion of the body unit frame for coupling and supporting a semi-trailer.
According to yet another aspect of the invention, the trailing portion of the body unit frame is movable between an extended position in which the axle assembly is positioned beyond the end of the body and a retracted position in which the axle assembly is disposed beneath the body. The retracted position of the axle assembly allows the body to be backed to a loading dock to facilitate loading and unloading. The body unit frame may include main frame rails having a profile defining a channel and the trailing portion of the body unit frame includes frame rails slidably nested in the channel of the body unit main frame rails.
According to the invention, the fifth wheel on the truck tractor frame is mounted for sliding for selectively positioning the fifth wheel on the truck tractor frame in a forward position (i.e., adjacent the truck tractor cab) and a rear position (i.e., adjacent a rear of the truck tractor frame).
According to another aspect of the invention, the axle assembly of the body unit is a steerable axle, and may be a self-steering axle or powered steering axle. According to another aspect, the steerable axle may be convertible between steerable and fixed axle functions.